circuit controlling system



Dec. 16, 1941. E. w SEEGER T A Re. 21,980

CIRQUIT CONTROLLING SYSTEM -ori ina1 Filed Sept1 4, 1 9:5?

,LI a 1 L3 EQAW' Q80. 56 I k /m gbmw Reissued Dec. 16, 1941 CIRCUITCONTROLLING SYSTEM Edwin W. Seegcr, Wauwatosa, and Glendon C. Brown,deceased, late of Wauwatosa, Wis., by Cutler-Hammer, Inc., Milwaukee,Wis., assignee Original No. 2,164,087, dated June 27, 1939, Serial No.162,544, September 4, 1937.

Application for reissueMay 22, 1941, Serial No. 394,738

12 Claims.

The present invention relates to circuit controlling systems, and moreparticularly to systems requiring provision for time elements.

Where electronic apparatus such as an X-ray .tube having a heatedcathode is to be energized to conduct current tor a given period it isimportantthat the heater cathode be at a substantially normaltemperature before the main discharge circuit is energized in order toavoid injury to the cathode. Also it is often necessary to time theperiod of energization of the X-ray tube very accurately to preventover-exposure with resulting damage to the exposed object, and .it isdesirable that after an exposure period the circuit be rendered inactivepending manual operation of a pilot switch.

An object of the present invention is to provide a simple and effectivesystem affording the desired control of such X-ray tubes and otherdevices. Another object is to provide a system affording graduation ofthe power supplied to the X-ray tube or other translating device, and toafiord a time limit to supply of power at one value and also time limitto supply of power at 'another value.

;Another object is to provide a system which afiords such time limitwith accuracy and which if desired may be designed to insureagainst-repeated cycles of operation except upon manual operation'of apilot switch.

Other objects and advantages will hereinafter appear.

The accompanying drawing illustrates diagrammatically one embodiment ofthe invention which will now be described, it being understood that Kthe embodiment illustrated is susceptible of modification withoutdeparting from the scope of the appended claims.

Referring to the drawing, there is shown an X-ray tube 1 to be suppliedwith energy from lines L and L supplied with alternating current. Thetube I which has a heated cathode 2 has its main electrodes connectedacross secondary winding 3 ofa'transformer 4 which has a primary winding5 and another secondary winding 5. The secondary winding 6 is connectedto the terminals or the cathode 2 and supplies the heating energy forsaid cathode.

A relay I has an energizing winding 8 connected in series with aresistance 9 across the I1ine'L L This relay has normally disengagedcontacts Ill preferably paralleled by high im- 'pedance or indicatinglamp-I I. The contacts Ill control a circuit for th primary winding oftransformer 4 which circuit includes an impedance l2 with which isassociated a secondary winding l3. The winding I3 is connected toabimetallic strip 14*ands'aid winding when energized supplies tosaidyst'rip heating current. The .bimetallic strip :14 has associatedtherewith contacts l5, l6 and I1 and constitutes a timing switch. Thecontact l5 normally engages contact I6 and disengages said contact ItWhen the strip is heated. Further movement of contact l5 efiects itsengagement with the normally disengaged contact H. The contact IT isconnected to line L while contact I6 is connected to a point between thewinding 3 of relay 1 and resistance 9, said contact IE being alsoconnected to contact l5 through a resistance 9.

A relay l8 having a winding I9 is provided with stationary contacts 20and 2| and a movable bridging contact 22, the latter normallydisengaging said stationary contacts. The winding 19 of the relay isconnected between contact l5 of the timing switch and lineL The contact22 of relay I8 is connected to a point between contact I5 and theterminal of winding H! which is connected to contact l5. Contact 29 isconnected to line L and contact 2! is connected to a point betweenimpedance l2 and the contacts ll! of relay 1.

The primary winding 5 of transformer 4 has one terminal connectedthrough contacts Ill of relay 1 to and through impedance l2 to line Lwhile the other terminal of winding 5 is connected to line L lines L andL being connected to a suitable source through a manual pilot switch 23.

With the switch 23 closed and the time switch in normal position currentflows from line L by conductor 25 through the winding -8 of relay I byconductors 26 and 21 through resistance 9 to line L The relay 1 is thusenergized and engages its contacts M3 to complete a circuit from line Lthrough impedance l2 to and through the primary winding 5 of transformer4 to line L The transformer 4 is thus energized at a reduced voltage sothat the potential impressed on the tube l is not sufiicient to producedischarge. However, the secondary winding 6 is excited to supplysufficient heating current to the cathode 2 to bring it to the propertemperatur within a short period.

The winding I2 being now energized induces a current in winding 13 whichheats up the bimetallic strip I4 and after lapse of a given timeaccording to the design and adjustment of the time switch the contact l5disengages contact l6 and engages contact ll. When the contact l5engages contact ll it closes a circuit from line L over contacts lI-l5,coil l9, to line L thus energizing relay H! which bridges contacts 29-2l22. A second circuit is thereby established from line L over contactsll-IE, contacts 22-2|, through impedance 1! to line L thusshort-circuiting the impedance l2 whereby full line voltage is impressedon the transformer winding 5 to cause the tube l to discharge. ,Alsorelay l8 in responding establishes for itself a maintaining circuitindependent of the timing switch. This maintaining circuit may be tracedfrom line L by conductors 25 and 29 to contact 20 and bridging contact22 by conductor 35] to and through winding I9 to line L When theimpedance I2 is short-circuited the bimetallic strip I4 is permitted tocool and after lapse of a given time the contact I5 disengages contactI! and shortly thereafter reengages contact I6. Reengagement of contactI5 with contact I6 short-circuits the winding 8 of relay I causing saidrelay to release to insert impedance II in series with the transformerWinding 5 for stopping discharge of the tube I. The shortcircuit for theWinding 8 of relay I extends from line L by conductors 25 and 29 throughthe contacts 20 and 22 of relay 8 by conductors 3i) and 28 throughcontacts I5 and I6 of the timing switch to and through resistance 9 toline L When relay 1 releases relay I8 remains energized due to itsself-established maintaining circuit and thus before the tube I may becaused to discharge again th pilot switch 23 must be opened todeenergize relay I8. When the relay I8 opens it interrupts theshort-circuit of the winding 8 of relay 1 whereupon the system isprepared for a further cycle of operation upon reclosure of switch 23.

The impedance II is of a high value, its purpose being to preventdischarge of tube I and high voltage transient impulses in thetransformer 4 if the contact In upon deenergization of relay 1 shouldvibrate and intermittently open and close the circuit.

The periods of operation may be adjusted in various ways, as forinstance by relative adjustment of the contacts I5, I6 and I! or byadjustment of the winding I3.

What we claim as new and desire to secure by Letters Patent is:

1. The combination with a translating device and a source of energytherefor, of an impedance, electroresponsive switches to establishenergy supply connections for said translating device inclusive andexclusive of said impedance, and control means for said switchescomprising a thermal switch associated with said impedance to bethermally influenced by the current traversing said impedance, saidthermal means controlling the time at which said impedance is excludedand determining the duration of the periods in which said switcheseffect supply of energy to said translating device with said impedanceincluded and with said impedance excluded.

2. The combination with a translating device and a source of energytherefor, of an impedance, electroresponsive switches to afford energysupply connections for said translating device and to include andexclude said impedance for graduation of the supply of said energy tosaid translating device, and control. means for such switches comprisinga manual pilot switch and timing means effective upon actuation of saidpilot switch, said timing means determining the time of exclusion ofsaid impedance and de termining the periods during which said switchesefliect supply of energy to said translating device with said impedanceincluded and with said impedance excluded, and said control meansinsuring against repetition of cycles except upon operation of saidmanual switch for each cycle.

3, The combination with a translating device,

,sourceof ener y therefor, of an impedyi "enema: 'i supplyconriection"for said translating device and to include and exclude said impedancefor graduation of the supply of energy to said translating device andcontrol means for said switches comprising a manual pilot switch and athermal switch associated with said impedance to be thermally influencedby the current traversing said impedance, said thermal switchdetermining the time of exclusion of said impedance and determining theperiods during which said switches effect supply of energy to saidtranslating device with said impedance included and with said impedanceexcluded, and said con trol means insuring against repetition of cyclesexcept upon operation of said manual switch for each cycle.

4. The combination with a source of energy and a translating device tobe supplied thereby, of an impedance, an electroresponsive switch toaiTord a connection for said translating device to said source throughsaid impedance, a second electroresponsive switch to short circuit saidimpedance, and control means for said switches including a thermalswitch associated with said impedance and thermally responsive tocurrent in said im,- pedance, said means in a given position of saidthermal switch effecting response of said first mentioned switch andsaid thermal switch thereafter, but subject to a predetermined delay,efiecting response of said second mentioned switch and after a furtherpredetermined delay effecting deenergization of said first mentionedswitch.

5. The combination with a source of energy and a translating device tobe supplied thereby, of an impedance, an electroresponsive switch toafford a connection for said translating device to said source throughsaid impedance, a second electroresponsive switch to short circuit saidimpedance, and control means for said switches including a thermalswitch associated with said impedance and thermally responsive tocurrent in said impedance, said means in a given position of saidthermal switch efiecting response of the first mentioned switch and saidthermal switch thereafter, but subject to a predetermined delay,effecting response of said second switch and after a furtherpredetermined delay efiecting deenergization of said first mentionedswitch, and said control means further including a manual switchrequiring operation to deenergize said second mentioned switchpreparatory to repetition of the cycle of control.

6. The combination with a translating device and a source of energytherefor, of an impedance, a thermal switch responsive to the current insaid impedance and having contacts normally closing one circuit gap andnormally opening another circuit gap, an electroresponsive switch toestablish a supply connection between said source of energy and saidtranslating device through said impedance and a second electroresponsiveswitch responsive to short-circuit said impedance and having itsenergizing winding connected in a circuit which includes the contacts ofsaid thermal switch which normally open the circuit gap and connectionscompleted by said second electroresponsive switch when energized and bythe contacts of said thermal switch which normally close the circuit gapto short-circuit the first mentioned electroresponsive switch.

7. The combination with a translating device and a source of energytherefor, of an impedance, a thermally responsive switch responsive tothe ser n in sai im edamasa d swi having a plurality of ctiitaas'certain of whieirai'htrmally engaged and certain of which are normallydisengaged, being eng'ageable after disengagement of the first mentionedcontact, an electroresponsive switch controllable at will to connectsaid translating device to said source of energy through said impedance,a second electroresponsive switch responsive to short-circuit saidimpedance, said second electroresponsive switch having an energizingcircuit to be closed upon engagement of the normally disengaged contactsof said timing switch and having a maintaining circuit independent ofsaid thermal switch, and a short-circuit for the operating winding ofthe first mentioned electroresponsive switch controlled jointly by thenormally engaged contacts of said thermal switch and contacts of saidsecond electroresponsive switch.

8. The combination with a translating device and a source of energytherfor, of a transformer having a primary winding and a secondarywinding, a thermally responsive switch connected to said secondarywinding to be thermally responsive to the current therein, said thermalswitch having a movable contact element and cooperating contacts to beengaged thereby selectively, said element normally engaging one of saidcontacts, an electroresponsive switch responsive to establish aconnection between said translating device and said source includingsaid transformer primary winding, a second electroresponsive switchresponsive to short-circuit said transformer primary winding andenergizable by engagement of the normally disengaged contacts of saidthermal switch and having a maintaining circuit independent of saidthermal switch and a short-circuit for the energizing winding of thefirst mentioned electroresponsive switch controlled jointly by contactsof said second electroresponsive switch and the normally engagedcontacts of said thermal switch.

9; The combination with a transformer and a source of energy therefor, asecond transformer, an electroresponsive switch to complete a connectionbetween the primary winding of the first mentioned transformer and saidsource, through the primary winding of the second transformer, a thermalswitch supplied with heating current by the secondary winding of thesecond mentioned transformer, an electroresponsive switch controlled bysaid thermal switch to short-circuit the primary winding of the secondmentioned transformer following response of the first mentioned switchbut subject to a predetermined delay, and a short-circuit for theoperating winding of said first mentioned switch controlled jointly bysaid second electroresponsive switch and said thermal switch fordeenergizing the first mentioned switch following response of saidsecond electroresponsive switch but subject to a predetermined delay.

10. The combination with a transformer and a source of energy therefor,a second transformer, an electroresponsive switch to complete aconnection between the primary winding of the first mentionedtransformer and said source through the primary winding of the secondtransformer, a thermal switch supplied with heating current by thesecondary winding of the second mentioned transformer, anelectroresponsive switch controlled by said thermal switch toshort-circuit the primary winding of the second mentioned transformerfollowing response of the first mentioned switch but subject to apredetermined delay and a short-circuit for the operating winding ofsaid first mentioned switch controlled jointly by said secondelectroresponsive switch and said thermal switch for deenergizing thefirst mentioned switch following response of said secondelectroresponsive switch but subject to a predetermined delay, and amaintaining circuit for said second electroresponsive switch independentof said thermal switch.

11. The combination with a source of energy and a translating device tobe supplied thereby, of control means to complete at will connectionsbetween said source of energy and said translating device inclusive ofan impedance, then to exclude said impedance from circuit automatically,and then after a limited time to render said translating deviceineffective pending subsequent manual operation of an element of saidcontrol means, said control means including electroresponsive switchesand a double throw thermally responsive switch subject to thermalinfluence of current derived from said source one of saidelectroresponsive switches being responsive, following manual initiationof a cycle of operation, to exclude said impedance from the circuit ofsaid translating device to render the latter active and the other ofsaid electroresponsive switches being responsive subject to control bysaid thermally responsive switch to eliminate the aforementioned thermalinfluence and subsequently to coact with said thermally responsiveswitch to render said translating device ineffective and in so doing todeenergize said first mentioned electroresponsive switch, said secondmentioned electroresponsive switch establishing for itself a maintainingcircuit requiring for its interruption the aforementioned manualoperation,

12. The combination with a source of energy and a translating device tobe supplied thereby, of control means to complete at will connectionsbetween said source of energy and said translating device inclusive ofan impedance, then to exclude said impedance from circuit automatically,and then after a limited time to render said translating deviceineffective pending subsequent manual operation of an element of saidcontrol means, said control means including electroresponsive switchesand a double throw thermally responsive switch subject to thermalinfluence of current derived from said source, one of saidelectroresponsive switches being responsive, following manual initiationof a cycle of operation, to exclude said impedance from the circuit ofsaid translating device to render the latter active and the other ofsaid electroresponsive switches being responsive subject to control bysaid thermally responsive switch to eliminate the aforementioned thermalinfluence, and subsequently to coact with said thermally responsiveswitch to deenergize said first mentioned electroresponsive switch andreinclude said impedance in circuit with said translating device, saidsecond mentioned electroresponsive switch establishing for itself amaintaining circuit requiring for its interruption the aforementionedmanual operation.

EDWIN W. SEEGER. CUTLER-HAMMER, INC., Assignee of Glendon C. Brown,Deceased,

By GRAULEY S. CRANE,

Vice President.

